1. Field of the Invention
The present invention relates generally to an ink cartridge used for supplying ink to a recording head in an ink jet recorder, and more particularly, to an ink cartridge capable of stably supplying ink to a recording head.
2. Description of the Related Art
Conventionally, in discharging ink from a recording head to record image using in an ink jet recorder, ink contained in an ink cartridge is supplied to the recording head from the ink cartridge.
Various ink cartridges have been conventionally used as such an ink cartridge. One example of the ink cartridge is an ink cartridge as shown in FIG. 1.
In the ink cartridge, an ink supply port 11 for supplying ink 1 to a recording head (not shown) is provided in a bottom surface 10a of a cartridge 10 formed in a box shape. The vent hole 12 for introducing air into the cartridge 10 is provided in a lower part of a side surface 10b, which is spaced apart from the ink supply port 11, of the cartridge 10. A partition plate 13 having a plurality of holes is provided in the cartridge 10. The partition plate 13 separates the cartridge 10 into an ink containing section 14 containing the ink 1 and a holding member containing section 15 containing an ink holding member 20 composed of a sponge or the like for holding ink. The ink 1 is contained in the ink containing section 14, and the ink 1 is held in the ink holding member 20 in the holding member containing section 15.
In the ink cartridge, the ink 1 held in the ink holding member 20 provided in the cartridge 10 is supplied to the recording head through the ink supply port 11, while the air is introduced into the cartridge 10 through the vent hole 12, to keep the inside of the cartridge 10 at a predetermined pressure.
When the ink in the ink cartridge is supplied to the recording head at high speed, for example, at the time of purging when the ink is supplied to the recording head through the ink supply port 11 at a speed which is approximately 10 to 100 times the normal speed in order to clean the recording head, air introduced into the cartridge 10 from the vent hole 12 is introduced into the ink supply port 11 through a clearance between the ink holding member 20 and an inner wall of the cartridge 10, for example. The air, taking the form of air bubbles, is introduced into the recording head through the ink supply port 11, and the recording head is clogged with the air bubbles, whereby the ink cannot be satisfactorily discharged, resulting in insufficient printing, for example.